STUDY OF THE RADIATION EMITTED BY A RADIO BASE STATION ON NEAR-FIELD SITUATION R. M. Gerosa; C. B. Monteiro; Y. M. B. M. de Oliveira; L. C. Barbosa Engineering School Mackenzie University São Paulo, Brazil rodrigo_mgerosa@mackenzista.com.br cibellebm@terra.com.br yaraoliveira@mackenzie.br lcbarbosa@mackenzie.br Abstract— This paper shows a study of the electromagnetic radiation in near-field situations for a radio-base mobile antenna. Through a routine developed in Matlab the electric field, the magnetic field and the power density are calculated, and the results are compared with Brazilian standards and ICNIRP limits. The obtained results show that for smaller distances to the antenna the values of electric and magnetic fields and power density are above the ones required by Brazilian standards. Keywords: electromagnetic radiation. radio base station. near field. I. INTRODUCTION The development of telecommunications technology, along with the incessant quest for modernity, practicality and especially mobility, is providing an accelerated growth in the use of mobile phones. Even those who are reluctant to buy those equipments are surrounded by radio base stations, which may be installed on the ground next to their homes or even on top of their apartment buildings. The antennae of the radio base stations transmit and receive electromagnetic waves (electromagnetic radiation) that allow communication between mobile phones. The interaction with these telephone systems is inevitable and affects everyone, making no distinctions, therefore, together with the great convenience this technology provides, the population is also subject to possible adverse effects that electromagnetic radiation may cause. The radio base stations antennae produce a kind of electromagnetic radiation classified as non-ionizing, once they operate on frequencies that do not have enough energy to break chemical bonds, meaning they cannot change atoms and therefore are not capable of releasing ions, unlike ionizing radiation (X rays, gamma, etc.). The mechanism of interaction of non-ionizing radiation with biological systems can be grouped into two types: thermal effects and non-thermal effects, depending on whether they are attributable to dissipation of heat (thermal), or the direct interaction of electromagnetic waves with the substance of the tissue, without significant component of heat. The most apparent biological effect in the frequencies used by mobile phones is the thermal type.[1]. According to exposition they can be classified in two types: occupational (or controlled) which is considered for adults, aware of the risk and exposed for a fixed period of time, and not controlled (or the general population), which includes all types of people of all ages not aware of the risks and subjected to radiation up to 24 hours a day.[2] Each day this issue gains more notoriety in the media, creating much controversy and a growing concern of society and of both public and private organs. Many articles are being published and a large number of searches are being conducted around the world in order to uncover the real effects of such radiation in humans. The results are still very controversial and unclear, and most do not present convincing evidence on possible adverse effects on both the exposure of the general population and occupational exposure, especially when it comes to non-thermal effects of such radiation. Worldwide, regulatory agencies and government bodies are imposing limits on exposure and providing technical safety criteria for installation of the antennae of radio base stations of mobile telephones. However, the concerns focus on the population in general. Most studies consider this type of exposure and use simpler calculations by dealing with lager electromagnetic fields, while for occupational exposure in near-field condition, there is a rather more complex mathematical formalism to determine the intensity of radiation in small distances between the receiver (person) and the transmitting source (antenna). There aren't many studies that emphasize the aspect of exposure to near field, related to professionals (people) who spend the day (or several hours) in the stations, in other words, in small distances of the sources that generate electromagnetic radiation. It is intended in this article to present a study of the electromagnetic radiation emitted by radio base stations of mobile telephony, in near-field situation. Calculations of electromagnetic fields were made, considering real antennae information, and the conditions of exposure in different lengths in near-field situations were analyzed, comparing the values 978-1-4244-5357-3/09/$26.00©2009IEEE 811